JP2011013611A - Pellicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pellicle that is reliably stuck to a photomask and stably maintain the stuck state for a long period of time.SOLUTION: The pellicle includes a pellicle film, a pellicle frame and an adhesive layer, wherein the pellicle film is stretched on the upper end face of the pellicle frame, and the adhesive layer is applied on the whole perimeter of the end face of the pellicle frame so as to stick the pellicle frame to a substrate. The adhesive layer has a cross section of an inverted dome shape in a width direction, and a ratio (H/W) of the height (H) to the width (W) in the cross section is 0.13 or more and 1.0 or less. The pellicle is reliably stuck to the photomask and the stuck state is stably maintained for a long period of time.

Description

  The present invention relates to a pellicle suitable for lithography, which is used as a dust remover when manufacturing semiconductor devices, printed boards, liquid crystal displays, and the like. In particular, the present invention relates to a pellicle in which the cross-section in the width direction of the adhesive layer of the pellicle frame is an inverted dome shape.

  In the manufacture of semiconductors such as LSI and VLSI, and in the manufacture of liquid crystal displays and the like, a pattern is produced by irradiating a semiconductor wafer or liquid crystal master plate with light. A photomask or reticle (hereinafter simply referred to as a photomask) used at this time is used. If the dust adheres to the (describe), there is a problem that the edges, and the size, quality, appearance, etc. are impaired, such as the edges become gritty and the ground becomes dirty.

  For this reason, these operations are usually performed in a clean room, but it is still difficult to keep the photomask clean. Therefore, a method is generally employed in which exposure is performed after a pellicle is attached to the photomask surface as a dust remover. In this case, the foreign matter does not adhere directly to the surface of the photomask but adheres to the pellicle. Therefore, if the focus is set on the pattern of the photomask during lithography, the foreign matter on the pellicle becomes irrelevant to the transfer.

  In general, a pellicle has a transparent pellicle film stretched on the upper end surface of the pellicle frame, and an adhesive layer for attaching to a photomask is formed on the lower end surface. A release layer (separator) is detachably attached to the end face. Specifically, a transparent pellicle film made of nitrocellulose, cellulose acetate, fluororesin, etc. that transmits light well is applied to the upper surface of a pellicle frame made of aluminum, stainless steel, polyethylene, etc. Adhering by air drying (Patent Document 1: Japanese Patent Laid-Open No. 58-219023) or by adhering with an adhesive such as acrylic resin or epoxy resin (Patent Document 2: US Pat. No. 4,861,402, Patent Document 3) In addition, an adhesive layer made of polybutene resin, polyvinyl acetate resin, acrylic resin, silicone resin or the like for adhering to the photomask is provided on the lower end surface of the pellicle frame, and if necessary, Accordingly, a release layer (separator) for the purpose of protecting the pressure-sensitive adhesive layer is attached.

  When using the pellicle, the release layer (separator) is peeled off, and the pellicle adhesive layer is attached by applying pressure to the photomask and pressing it. The pattern is created by irradiating light with the pellicle facing downward, and is used for a long period of several years if it is long. If the adhesive peels off during long-term use and the pellicle falls, there is a possibility that the projection lens in the exposure apparatus is scratched and the exposure apparatus cannot be used. Also, even if it does not fall, if there is a gap between the pellicle frame and the adhesive layer, or between the adhesive layer and the photomask, dust will adhere to the photomask through the gap, The pellicle can no longer play the role. The pressure-sensitive adhesive layer must satisfy the condition that a gap cannot be formed between the pellicle frame and the pressure-sensitive adhesive layer and between the photomask and the pressure-sensitive adhesive layer even if the weight of the pellicle is applied for a long period of time.

  In addition, when a pellicle is attached to a photomask, it is necessary to apply the load with a load. However, if an excessive load is applied in order to apply the pellicle better, the expensive photomask may be broken.

JP 58-219033 US Pat. No. 4,861,402 Japanese Patent Publication No. 63-27707

  The present invention has been made in view of such circumstances, and provides a pellicle that can be reliably affixed to a photomask and can stably maintain its state over a long period of time. Objective.

  As a result of intensive studies to achieve the above object, the inventors of the present invention formed a pellicle adhesive layer for attaching the pellicle to a photomask, and formed a cross section in the width direction in an inverted dome shape, and By setting the ratio (H / W) of the width (W) of the pressure-sensitive adhesive layer to the height (H) of the pressure-sensitive adhesive layer in the range of 0.13 to 1.0, the pellicle photomask can be obtained. Has been found to be able to be reliably maintained over a long period of time, leading to the present invention.

Accordingly, the present invention provides the following pellicle.
Claim 1:
A pellicle film, a pellicle frame, and an adhesive layer, wherein the pellicle film is stretched on an upper end surface of the pellicle frame, and the adhesive layer can be attached to the substrate under the pellicle frame. A pellicle provided over the entire periphery of the end surface, wherein the cross-sectional shape in the width direction of the pressure-sensitive adhesive layer is an inverted dome shape, and the width (W) and height (H) of the cross-section The ratio (H / W) of the pellicle is 0.13 or more and 1.0 or less.
Claim 2:
The pellicle according to claim 1, wherein the pressure-sensitive adhesive is a silicone pressure-sensitive adhesive.

  The pellicle of the present invention can reliably adhere to a photomask and can stably maintain the state over a long period of time.

It is a longitudinal cross-sectional view which shows one Embodiment of the pellicle of this invention whose cross-sectional shape of the width direction of an adhesive layer is a reverse dome shape, (B) is a partial expanded longitudinal cross-sectional view of (A). In this invention, it is a schematic diagram which shows an example of the adhesive coating device used suitably for formation of an adhesive layer.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 is a longitudinal sectional view showing an embodiment of a pellicle of the present invention in which the shape of a cross section in the width direction of an adhesive layer is an inverted dome shape. In this pellicle 1, a pellicle film 11 is formed on the upper end surface of a pellicle frame 12 having a normal square frame shape (rectangular frame shape or square frame shape) corresponding to the shape of a substrate (photomask or glass substrate portion) to which the pellicle 1 is attached. A pressure-sensitive adhesive layer 13 is attached to the lower end surface of the pellicle frame 12 so as to attach the pellicle to the substrate. A release layer (separator) 14 for protecting the pressure-sensitive adhesive layer 13 is detachably attached to the lower end surface of the pressure-sensitive adhesive layer 13. In FIG. 1, W represents the width of the pressure-sensitive adhesive layer, and H represents the height of the pressure-sensitive adhesive layer.

  Here, the material of the pellicle film and the pellicle frame is not particularly limited, and a known material can be used, and the pellicle film is bonded to the pellicle frame by a known method.

  In the present invention, the pressure-sensitive adhesive layer is provided on the lower end surface of the pellicle frame with a predetermined width (usually equal to or less than the frame width of the pellicle frame), and extends over the entire circumference in the circumferential direction of the lower end surface of the pellicle frame. The pellicle frame is formed so that it can be attached to the substrate. In the present invention, the pressure-sensitive adhesive layer has a cross-section in the width direction (the frame width direction of the pellicle frame) surrounded by an inverted dome shape (for example, one straight line and one arc) In addition to semicircular and semi-elliptical shapes, the shape of the circle or ellipse is divided by its chord, such as a bow.) The plane side of the adhesive layer (straight side of the cross section) is the pellicle It is in contact with the lower end surface of the frame, and is provided with the curved surface side (arc side of the cross section) of the pressure-sensitive adhesive layer facing downward (in a convex state downward).

  At this time, the ratio (H / W) between the width (W) and the height (H) of the cross section in the width direction of the pressure-sensitive adhesive layer is in the range of 0.13 or more and 1.0 or less, and further 0.13 or more. A range of 0.5 or less is more preferable. If H / W is greater than 1.0, not only is it difficult to form an adhesive layer, but also the pellicle frame and pellicle film are distorted when attached to a photomask, resulting in deviation. On the other hand, if H / W is smaller than 0.13, the adhesive strength with the photomask is weakened.

  Application of the adhesive to the pellicle frame can be performed by, for example, a coating apparatus. FIG. 2 is a schematic diagram showing an example of an adhesive coating apparatus that is preferably used for forming an adhesive layer in the present invention. This adhesive application device 2 is attached above the pedestal 21 via a three-axis robot 22 configured by combining a fixed rail and a movable rail so that the syringe 23 can be moved in the XYZ axial directions. ing. A needle 25 is attached to the tip of the syringe 23, the syringe 23 filled with adhesive is connected to an air pressurizing dispenser (not shown), and a robot operation is performed by a control unit (not shown) of the three-axis robot 22. And both coating liquid discharge are controlled. Then, on the pellicle frame 24 set on the gantry 21 of the adhesive application device 2 (in this case, the top and bottom of the pellicle frame are arranged in reverse, and the above-described lower end surface of the pellicle frame faces upward). The adhesive can be applied onto the pellicle frame 24 by moving the adhesive while dropping from the needle 25. The adhesive may be applied not only once on the pellicle frame but also several times in order to obtain a predetermined adhesive layer height.

  In addition, when apply | coating an adhesive several times, it is better to provide a stationary time suitably between each rotation until the shape of the adhesive after application | coating is stabilized.

  Further, when the pressure-sensitive adhesive has a high viscosity and it is difficult to apply with a coating apparatus, the adhesive may be appropriately diluted with an organic solvent, alcohol, water, or the like to reduce the viscosity of the pressure-sensitive adhesive.

  In addition, the adhesive transfer means (not shown) is not limited to gas pressurization such as air pressurization or nitrogen pressurization, but can be supplied, discharged, and stopped, such as a syringe pump, a plunger pump, and a tube pump. Various transfer means that can be controlled are available.

  As said adhesive, silicone adhesives, such as a silicone resin adhesive, can be used conveniently. As a silicone adhesive, a well-known thing can be used, for example, the silicone adhesive commercially available from Shin-Etsu Chemical Co., Ltd. (for example, silicone adhesive X-40-3122, KR-3700, X- 40-3103, X-40-3068, etc.) can be used. In particular, X-40-3122 is preferable because it has high adhesive strength and reduces low-molecular-weight siloxane.

  The release layer (separator) is for protecting the adhesive layer until the pellicle is attached to the substrate, and is removed when the pellicle is used. Therefore, the release layer (separator) is appropriately provided when it is necessary to protect the pressure-sensitive adhesive layer until the pellicle is used. The product pellicle is generally distributed with a release layer (separator) attached thereto. There is no restriction | limiting in particular also in the material of a release layer (separator), A well-known thing can be used, and a release layer (separator) should just be affixed on an adhesive layer by a well-known method.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1]
First, the outer dimension is 782 × 474 mm, the inner dimension is 768 × 456 mm, and the height is 5.0 mm. Both the inner and outer edges on the upper end surface and the lower end surface side are R-processed, and the flat surfaces on both end surfaces However, a rectangular aluminum alloy pellicle frame having a width of 4.0 mm, an inner dimension R of 2.0 mm, and an outer dimension of R 6.0 mm was manufactured by machining, and the surface was black anodized. This pellicle frame was carried into a clean room and thoroughly washed and dried with a neutral detergent and pure water.

  Next, the pellicle frame 24 was fixed on the gantry 21 of the pressure-sensitive adhesive coating apparatus 2 shown in FIG. 2 so that the lower end surface (pressure-sensitive adhesive coating end surface) of the pellicle frame 24 was horizontal upward. In order to prevent the pellicle frame 24 from being bent due to its own weight and to keep the adhesive surface horizontal, support (not shown) made of polyacetal (POM) resin is provided on each side below the pellicle frame 24 at intervals of about 200 mm. It was.

  Then, a silicone adhesive X-40-3122 (manufactured by Shin-Etsu Chemical Co., Ltd .: product name) diluted to 50% with toluene as an adhesive is made of polypropylene (PP) of the adhesive applicator 2 shown in FIG. The syringe 23 was filled. The syringe 23 is connected to an air pressurizing dispenser (manufactured by Iwashita Engineering Co., Ltd., not shown), and both the robot operation and the coating liquid discharge are controlled by the control unit (not shown) of the three-axis robot 22 to automatically operate. Thus, the adhesive was dropped from the needle 25 on the entire circumference of the lower end surface of the pellicle frame 24 (facing upward when applied), and the adhesive was applied to the flat portion of the lower end surface. The cross-sectional shape in the width direction of the pressure-sensitive adhesive layer is an inverted dome shape (when it is applied, it becomes a convex dome shape), and the width of the pressure-sensitive adhesive layer is 4.0 mm and the height is 1.3 mm (H / W = Approx. 0.33), the adhesive was applied to the pellicle frame 24 in three times (three rounds).

  Then, after air-drying until the pressure-sensitive adhesive stops flowing, the pellicle frame is further heated to 130 ° C. by a high-frequency induction heating device (not shown) to completely evaporate the solvent and cure the pressure-sensitive adhesive. An adhesive layer was formed.

  Further, a silicone pressure-sensitive adhesive (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-3700) was applied to the upper end surface of the pellicle frame as an adhesive for the pellicle film. Then, the pellicle film was attached to the adhesive-coated end face side of the pellicle frame, and the outer unnecessary film was removed with a cutter to complete the pellicle.

[Example 2]
Adhesive pellicle so that the cross-sectional shape in the width direction of the adhesive layer is an inverted dome shape, the width of the adhesive layer is 4.0 mm, and the height is 0.5 mm (H / W = 0.13) A pellicle was produced in the same manner as in Example 1 except that it was applied to the frame.

[Example 3]
Adhesive pellicle so that the cross-sectional shape in the width direction of the adhesive layer is an inverted dome shape, the width of the adhesive layer is 4.0 mm, and the height is 4.0 mm (H / W = 1.0) A pellicle was produced in the same manner as in Example 1 except that it was applied to the frame.

[Comparative Example 1]
Adhesive pellicle so that the cross-sectional shape in the width direction of the adhesive layer is an inverted dome shape, the width of the adhesive layer is 4.0 mm, and the height is 0.2 mm (H / W = 0.05) A pellicle was produced in the same manner as in Example 1 except that it was applied to the frame.

[Comparative Example 2]
Adhesive pellicle so that the cross-sectional shape in the width direction of the pressure-sensitive adhesive layer is an inverted dome shape, the width of the pressure-sensitive adhesive layer is 4.0 mm, and the height is 5.0 mm (H / W = 1.3) A pellicle was produced in the same manner as in Example 1 except that it was applied to the frame.

  The pellicle produced in Examples 1 to 3 and Comparative Examples 1 and 2 was attached to a glass substrate, and a reliability test was performed. The conditions for attaching to the glass substrate and for the reliability test are as follows.

  The pellicle was placed on a glass substrate with the pressure-sensitive adhesive layer side down, and a pressure of 10 MPa was applied to the pellicle frame for 5 minutes with a press to attach the pellicle to the glass substrate. The prepared sample for evaluation was placed in an oven so that the top and bottom of the sample were replaced, and the pellicle was on the lower side, and a high temperature durability test was conducted at 80 ° C. for 1000 hours. The results are shown in Table 1.

1 Pellicle 11 Pellicle Film 12 Pellicle Frame 13 Adhesive Layer 14 Release Layer (Separator)
2 Adhesive Application Device 21 Base 22 Triaxial Robot 23 Syringe 24 Pellicle Frame 25 Needle W Adhesive Layer Width H Adhesive Layer Height

Claims (2)

  A pellicle film, a pellicle frame, and an adhesive layer, wherein the pellicle film is stretched on an upper end surface of the pellicle frame, and the adhesive layer can be attached to the substrate under the pellicle frame. A pellicle provided over the entire periphery of the end surface, wherein the cross-sectional shape in the width direction of the pressure-sensitive adhesive layer is an inverted dome shape, and the width (W) and height (H) of the cross-section The ratio (H / W) of the pellicle is 0.13 or more and 1.0 or less.   The pellicle according to claim 1, wherein the pressure-sensitive adhesive is a silicone pressure-sensitive adhesive.

Images